6/10/2019 Venomous Critters: Things That Bite and Sting Robert C. Allen, DO, FACEP Assistant Professor CASE Department UIW School of Osteopathic Medicine San Antonio, TX Overview: .Things That Bite: -Spiders -Venomous Snakes 1 6/10/2019 Overview: .Things That Sting -Scorpions -Hymenoptera -Bees -Wasps -Ants Think these Critters are Trouble? 2 6/10/2019 The Venomous Little Buggers Which is the deadliest in the United States? One reason “Why Animals Attack” 3 6/10/2019 Scorpions . 1,750+ species of scorpions known worldwide . All have venom, but only ~25 species are considered dangerous to humans . 18 species native to Texas, most stings are from to Centruroides vittatus, the striped bark scorpion -Centruroides sculpturatus, the only scorpion native to the US considered dangerous to humans, is occasionally found in the vicinity of El Paso 4 6/10/2019 Scorpions . Most significantly toxic species are in the family Buthidae -Centruroides (North America) -Tityus (Caribbean, Central & South America) -Leiurus (Middle East/Africa) -Androctonus(Middle East/Africa) -Buthus (Middle East/Africa) -Parabuthus(S. Africa) . Non-Buthidae: Hemiscorpiidae -Hemiscorpus lepturus (Iran) Scorpion stings in Texas: . Most scorpion stings are not significantly toxic -C. vittatus is the most commonly implicated species -Painful, about as serious as a bee sting -Local tenderness and inflammation common -Local paresthesia can occur -Rarely see any systemic signs/symptoms . Treatment: Ice, analgesics, check tetanus status 5 6/10/2019 Approximate U.S. distribution of the Arizona Bark Scorpion (C. sculpturatus) Vetter et al, American Entomologist V 64 No 2, pp 79-82 6 6/10/2019 Centruroides sculpturatus . Venom mainly neurotoxic, causes severe local pain but little local inflammation -Tap Test-Not clinically proven, but commonly used -Max severity in about 5 hours . Cranial nerve dysfunction/somatic skeletal neuromuscular dysfunction/autonomic dysfunction -HTN, tachycardia, CHF-like symptoms, blurred vision, roving eye movements, hypersalivation, tongue fasciculations, dysphagia, dysphonia, hyperthermia, restlessness, severe involuntary shaking/jerking motions . Respiratory arrest can occur 7 6/10/2019 C. sculpturatus . Pain control + mild symptom control can be done with IV fentanyl (less histamine release) and short-acting benzo’s . Severe stings: Antivenin (Anascorp) is available -FDA approved since 2011 -Equine-origin F(ab’)2 antivenin -Low incidence of allergic reactions -3 vials IV initial dose -1 vial every 30-60 min if needed x 2 . Watch the airway! Centruroides under UV light 8 6/10/2019 Other (non U.S.) Scorpions . Venom causes release of catecholamines -Significant pain at sting site -HTN -Pulmonary Edema -Sz can occur -Encephalopathy, pancreatitis, priapism have been reported --Yes, scorpion sings can be a cause of pancreatitis Treatment . Symptomatic Treatment usually effective -Pain Control (analgesia+sedation) . Some areas (Saudi Arabia) go with antivenin very early . India: Prazosin effective in treatment of Sx of severe Mesobuthis envenomation (pulmonary edema and hypertension) 9 6/10/2019 Hymenoptera Hymenoptera . Apis (Bees) . Vespids (Wasps) . Formicidae (Ants) . Sting is modified ovipositor -Venom: -Histamine, serotonin, melittin, Ach -Adolapin-has antiinflamatory properties 10 6/10/2019 Hymenoptera . Most stings are minor, local treatment only . How Painful? Western Honeybee: 2/4 on the Schmidt Scale (“Burning, corrosive, but you can handle it. A flaming match head lands on your arm and is quenched first with lye and then sulfuric acid.”) . Anaphylaxis to hymenoptera stings -Estimated 0.4-0.8% of children, 3% of adults -90-100 deaths per year from insect sting anaphylaxis . Desensitization therapy is successful about 85-95% of the time with bees, not as good with fire ants Hymenoptera . Anaphylaxis Treatment: -Remove stinger -Epinephrine (IM, not Sub Q!), airway, fluids, H-1 and H-2 blockers, steroids -Observe! . Allergy consult, epi kit BEFORE discharge! 11 6/10/2019 New Design EpiPen 12 6/10/2019 AUVI-Q Hymenoptera . Large local reaction -Swelling/erythema 15 cm beyond sting site -Persisting over 24 hours . Type IV reaction (Cell-mediated) -Systemic reactions rare -Consult Allergy/Immunology 13 6/10/2019 Hymenoptera . Africanized Honeybee: -Remember Monty Python: RUN AWAY! RUN AWAY! Hymenoptera . Massive hymenoptera stings: -40+ Vespid/200 + Apis stings, 500+ Fire Ant stings -Anaphlactoid reactions can occur -N/V/D, edema, dyspnea, hypotension -MI’s can result -Rhabdomyolysis can occur . Treat symptoms, consider admit if pt is old/young or poor health 14 6/10/2019 Hymenoptera . Massive stings (40-50+ vespid) -IV H-1 and H-2 blockers -IV Steroids -Treat shock/oliguria/myoglobinuria 15 6/10/2019 Hymenoptera-Formicidae . Fire Ants (Solenopsis invicta): -Bites, then swings around, stinging multiple times -Venom is mainly piperidine alkaloids, causes histamine release and necrosis -Sterile pustules form, usually within 24 hours . Anaphylaxis is a concern . Treatment is symptomatic . 1 out of 4 on the Schmidt Scale. (“Sharp, sudden, mildly alarming. Like walking across a shag carpet and reaching for the light switch.”) Fire Ant Distribution, U.S. 16 6/10/2019 Most Painful Sting in the US: Tarantula Hawk (Pepsis Spp) Getty Images National Park Service 4/4 on the Schmidt Scale: “If stung, lie down and start screaming” “Blinding, fierce, shockingly electric. A running hair drier has just been dropped in your bubble bath.” 17 6/10/2019 Spiders . Main Species of Concern: -Latrodectus (neurotoxic)-Worldwide -Atrax (neurotoxic)-Australia -Loxosceles (necrotic)- L.reculsa most commonly problematic . -Occasional problems with Phoneutria spp 18 6/10/2019 19 6/10/2019 Spiders-Latrodectus . Symptoms onset within 1 hour: -Severe muscle spasms, anxiety, diaphoresis, HTN, salivation -Severe cases: Ptosis, weakness, fasciculations . Control symptoms with IV opiates and benzo’s: Symptoms may last 2-3 days . Antivenin is available, not usually needed -In one case report, AV was effective 44 hours after envenomation -Reserve antivenin use for severe cases refractory to other treatment? 20 6/10/2019 Spiders-Loxosceles . Loxosceles: 5 species in the US implicated -Necrotic Arachnidism -No useful AV for species found in the U.S. -Majority require routine wound care -Dapsone 50-100 mg QD (Dose BID, start early) -Controversial-No good human studies -My opinion: Don’t use -Other Methods: Surgery, HBO, Steroids -Hemolytic anemia, DIC, hemoglobinuria, renal failure can occur (relatively rare) . Incidence greatly overestimated: -“It’s MERSA unless you see the spider bite you…” Copyrights apply 21 6/10/2019 Copyrights apply Day 3 Day 4 Brown Recluse Bite or MERSA?? Both? Day 6 22 6/10/2019 Day 9 Day 10 Famous Last Words: “Hey, Bubba! Hold My Beer and Watch This!!” 23 6/10/2019 24 6/10/2019 Prevention . #1: Don’t Play With The Snake . #2: Control Rodents (snake food) . #3: Don’t Mess With The Snake . #4: Don’t Reach or Step Into Unseen Areas . #5: Don’t Tease, Annoy, Fiddle With or Otherwise Scare The Snake 25 6/10/2019 Copyrights apply Snakebite First Aid . #1: Don’t Panic . #2: Don’t Make Things Worse . #3: Get To Medical Care As Quickly As Possible 26 6/10/2019 Snakebite First Aid Things That Don’t Work: . Alcohol (External or Internal) . Electrical Shock (Stun Gun) . ’Cut and Suck’ . Tourniquets . Ice Cutter Kit: Do not use this kit! 27 6/10/2019 Snakebite First Aid . ‘Extractor Pump’ -One study showed effective if applied within 5 minutes of bite -Recent Studies shows it is not effective, and may lead to increased necrosis at bite site First Aid . Pressure-Immobilization Technique -Appears to work in elapid, sea snake, most Australian snakes (i.e. neurotoxic-predominant venoms) -NOT recommended for bites by species with hemo/cytotoxic predominant venom (i.e. Pit Vipers) -IS recommended first aid for coral snake envenomation 28 6/10/2019 First Aid . Remove rings, any constricting items . Immobilize at heart level . Keep patient at rest as much as possible . Bring in the snake? -Not only no, but #$!@!! NO! Venom Types . All snake venoms have neurotoxic and hemo-cytotoxic components . Vipers, including old world vipers and pit vipers (crotalids) tend to have hemo/cytotoxic predominant components . Elapids (including the Coral Snake) tend to have neurotoxic- predominant components 29 6/10/2019 Venom Types . Elapids (cobras, kraits, coral snakes) sea snakes, and most Australian snakes have neurotoxic predominant venom . No hard/fast rules: King cobra bite can cause serious tissue destruction, several species of crotalids have significant neurotoxic effects -Most infamous: C. scutulatus, the Mojave Rattlesnake (AKA, the ‘Mojave Green’) Get Help!! .National Poison Information Hotline: 1-800-222-1222 30 6/10/2019 Clinical Evaluation . Not all bites result in injection of venom . Not all envenomations require antivenom treatment . Most snakebite victims will survive . Death from snakebite typically takes hours to days Clinical Evaluation . Hemo/cytoxic predominant venoms usually show: -Moderate to severe swelling, starting at bite site -Moderate to severe pain at the bite site -In crotalid bites, decreased platelets are one of the early signs of systemic envenomation. 31 6/10/2019 Clinical Evaluation . Neurotoxic predominant bites: -Can be almost painless -Show no symptoms for hours, followed by rapid deterioration -Bulbar paralysis, generalized weakness, salivation, weak respirations -If any neurologic signs/sx present, treat as a significant envenomation Copyrights